package com.example.opengl;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.security.KeyStore.LoadStoreParameter;
import android.hardware.Camera.Size;
import android.opengl.GLES20;

public class Triangle {
	
	 private final String vertexShaderCode = 
			 "uniform mat4 uMVPMatrix;" + 
			"attribute vec4 vPosition;" +  
					 "void main() {" +    
			"  gl_Position = vPosition * uMVPMatrix;" +      
			"}";
	 
	private final String fragmentShaderCode =
		    "precision mediump float;" +
		    "uniform vec4 vColor;" +
		    "void main() {" +
		    "  gl_FragColor = vColor;" +
		    "}";
		
	private final int mProgram;
	private int mPositionHandle;
	private FloatBuffer vertexBuffer;
    private int mColorHandle;
    private int mMVPMatrixHandle;

    /*static float triangleCoords[] = {
        // in counterclockwise order:
        1.0f,  0.5f, 0.0f,   // top
       0.5f, -0.3f, 0.0f,   // bottom left
        1.5f, -0.3f, 0.0f    // bottom right
    };*/
    
    float triangleCoords[] = {  //TRIANGULO EN EL MEDIO
            // X, Y, Z
            -0.5f, -0.25f, 0,
             0.5f, -0.25f, 0,
             0.0f,  0.559016994f, 0
        };
    
    // number of coordinates per vertex in this array
 	static final int COORDS_PER_VERTEX = 3;
 	
    private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
    private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
	
    //rgba
	float color[] = {1f,1f,0.0f,1f};

	public Triangle(){
		
        // initialize vertex byte buffer for shape coordinates
		ByteBuffer bb = ByteBuffer.allocateDirect(
                // (number of coordinate values * 4 bytes per float)
				triangleCoords.length * 4);
		
		 // use the device hardware's native byte order
        bb.order(ByteOrder.nativeOrder());
        
        // create a floating point buffer from the ByteBuffer
        vertexBuffer = bb.asFloatBuffer();
        // add the coordinates to the FloatBuffer
        vertexBuffer.put(triangleCoords);
        // set the buffer to read the first coordinate
        vertexBuffer.position(0);
        
        int vertexShader = MyGLRenderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
        int fragmentShader = MyGLRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);

        mProgram = GLES20.glCreateProgram();             // create empty OpenGL ES Program
        GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program
        GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
        GLES20.glLinkProgram(mProgram);                  // creates OpenGL ES program executables
    }		
	
	public void draw(float[] mvpMatrix) {
        // Add program to OpenGL environment
        GLES20.glUseProgram(mProgram);

        // get handle to vertex shader's vPosition member
        mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");

        // Enable a handle to the triangle vertices
        GLES20.glEnableVertexAttribArray(mPositionHandle);

        // Prepare the triangle coordinate data
        GLES20.glVertexAttribPointer(
                mPositionHandle, COORDS_PER_VERTEX,
                GLES20.GL_FLOAT, false,
                vertexStride, vertexBuffer);

        // get handle to fragment shader's vColor member
        mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");

        // Set color for drawing the triangle
        GLES20.glUniform4fv(mColorHandle, 1, color, 0);

        // get handle to shape's transformation matrix
        mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");

     // Pass the projection and view transformation to the shader
        GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);

        // Draw the triangle
        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);

        // Disable vertex array
        GLES20.glDisableVertexAttribArray(mPositionHandle);
    }
	
	
}
